I'm not educated on WHS 2011. One of the other members maybe though. Regardless though you would need to up-grade the current processor to start with to handle 64Bit.
I just didn't have enough information or confident enough to confirm it and say "yeah" that will work! and I still can't, it's not my area or one where I'm a 100% about things.
The Before You Build Windows Home Server Checklist